<template>
  <div>
    <!-- 评论列表 -->
    <div class="cmt-list" :class="{'art-cmt-container-1' : isShow,
    'art-cmt-container-2': !isShow}">
       <!-- 默认上来不检测触底事件 -->
     <van-list
        v-model="loading"
        :finished="finished"
        finished-text="没有更多了"
        @load="onLoad"
        offset="50"
        :immediate-check="false"
      >
      <!-- 评论的 Item 项 -->
      <div class="cmt-item" v-for="obj in commentsList" :key="obj.com_id">
        <!-- 头部区域 -->
        <div class="cmt-header">
          <!-- 头部左侧 -->
          <div class="cmt-header-left">
            <img :src="obj.aut_photo" alt="" class="avatar" />
            <span class="uname">{{ obj.aut_name }}</span>
          </div>
          <!-- 头部右侧 -->
          <div class="cmt-header-right">
            <van-icon
              name="like"
              size="16"
              color="red"
              v-if="obj.is_liking === true"
              @click="likeFn(true, obj)"
            />
            <van-icon
              name="like-o"
              size="16"
              color="gray"
              v-else
              @click="likeFn(false, obj)"
            />
          </div>
        </div>
        <!-- 主体区域 -->
        <div class="cmt-body">
          {{ obj.content }}
        </div>
        <!-- 尾部区域 -->
        <div class="cmt-footer">{{ formatDate(obj.pubdate) }}</div>
      </div>
     </van-list>
      <!-- 底部评论 -->
      <div>
        <!-- 底部添加评论区域 - 1 -->
        <div class="add-cmt-box van-hairline--top" v-if="isShow">
          <van-icon name="arrow-left" size="0.48rem" @click="$router.back()" />
          <div class="ipt-cmt-div" @click="changeShowFn">发表评论</div>
          <div class="icon-box">
            <van-badge :content="totalCount" :max="99">
              <van-icon name="comment-o" size="0.53333334rem" @click="moveFn"/>
            </van-badge>
            <van-icon name="star-o" size="0.53333334rem" />
            <van-icon name="share-o" size="0.53333334rem" />
          </div>
        </div>

        <!-- 底部添加评论区域 - 2 -->
        <div class="cmt-box van-hairline--top" v-else>
          <textarea
          placeholder="友善评论、理性发言、阳光心灵"
          v-fofo
          @blur="blurFn"
          v-model="commentText"
          ></textarea>
          <van-button
          type="default"
          :disabled='commentText.length === 0'
          @click="sendFn"
          >发布</van-button>
        </div>
      </div>
    </div>
  </div>
</template>

<script>
import { getCommentsListAPI, likeCommentAPI, unLikeCommentAPI, sendCommentAPI } from '@/api'
import dayjs from 'dayjs'
import relativeTime from 'dayjs/plugin/relativeTime' // 到指定时间需要的插件
import 'dayjs/locale/zh' // 集成中文
dayjs.extend(relativeTime)
dayjs.locale('zh')
export default {
  props: {
    artId: String
  },
  data () {
    return {
      commentsList: [], // 评论列表数组
      isShow: true,
      totalCount: 0, // 评论总数
      commentText: '', // 发布评论的内容
      loading: false,
      finished: false,
      lastId: null // 下一页评论数据的偏移量 评论id (第一页不需要传, axios遇到null忽略此参数)
    }
  },
  created () {
    this.getCommentListFn()
  },
  methods: {
    // 加载更多
    onLoad () {
      if (this.commentsList.length > 0) {
        this.getCommentListFn()
      }
    },
    // 获取评论列表
    async getCommentListFn () {
      const res = await getCommentsListAPI({
        artId: this.artId,
        offset: this.lastId // 偏移量
      })
      // console.log(res, 'res')

      // 判断是否还有数据
      if (res.data.data.results.length === 0) {
        this.finished = true
      }
      // 合并数据
      this.commentsList = [...this.commentsList, ...res.data.data.results]
      this.totalCount = res.data.data.total_count || ''
      this.lastId = res.data.data.last_id // 保存起来为了做分页
      // 关闭加载状态
      this.loading = false
    },
    // 发布评论功能
    async sendFn () {
      // console.log(this.commentText)
      const res = await sendCommentAPI({
        target: this.artId,
        content: this.commentText
      })
      // console.log(res)
      this.commentsList.unshift(res.data.data.new_obj)
      this.totalCount++
      this.commentText = ''
      document.querySelector('.like-box').scrollIntoView({
        behavior: 'smooth'
      })
    },
    // 点击评论 --> 滚动到评论区
    moveFn () {
      // 直接获取某个标签 调用scrollIntoView() 此标签自动滚到网页最上边
      document.querySelector('.like-box').scrollIntoView({
        behavior: 'smooth'
      })
    },
    // 评论输入框- 失去焦点
    blurFn () {
      setTimeout(() => {
        this.isShow = true
      })
    },
    // 点击发表评论 -> 输入框出现
    changeShowFn () {
      // this.$nextTick()  data数据改变 dom重绘 是异步的 先等dom结构更新完 再滚动
      this.isShow = false
      // 用js代码模拟滚动效果 不让高的挡住内容
      this.$nextTick(() => {
        window.scrollTo(0, document.documentElement.scrollHeight - window.innerHeight)
        // const list = document.querySelectorAll('.cmt-item')
        // if (list.length === 0) return
        // list[list.length - 1].scrollIntoView({
        //   behavior: 'smooth'
        // })
      })
    },
    // 评论点亮/取消点亮
    async likeFn (bool, obj) {
      if (bool === true) {
        // 点红心  显示 => 灰心
        await unLikeCommentAPI(obj.com_id)
        obj.is_liking = false
      } else {
        // 点灰心 显示 => 红心
        await likeCommentAPI(obj.com_id)
        obj.is_liking = true
      }
    },
    // 格式化时间 -- 多久之前
    formatDate (dateStr) {
      var a = dayjs()
      var b = dayjs(dateStr)
      const c = a.to(b)
      return c
    }
  }
}
</script>

<style scoped lang="less">
.cmt-list {
  padding: 10px;
  .cmt-item {
    padding: 15px 0;
    + .cmt-item {
      border-top: 1px solid #f8f8f8;
    }
    .cmt-header {
      display: flex;
      align-items: center;
      justify-content: space-between;
      .cmt-header-left {
        display: flex;
        align-items: center;
        .avatar {
          width: 40px;
          height: 40px;
          background-color: #f8f8f8;
          border-radius: 50%;
          margin-right: 15px;
        }
        .uname {
          font-size: 12px;
        }
      }
    }
    .cmt-body {
      font-size: 14px;
      line-height: 28px;
      text-indent: 2em;
      margin-top: 6px;
      word-break: break-all;
    }
    .cmt-footer {
      font-size: 12px;
      color: gray;
      margin-top: 10px;
    }
  }
}

/*美化 - 文章详情 - 底部的评论页面 */
// 外层容器
.art-cmt-container-1 {
  padding-bottom: 46px;
}
.art-cmt-container-2 {
  padding-bottom: 80px;
}

// 发布评论的盒子 - 1
.add-cmt-box {
  position: fixed;
  bottom: 0;
  left: 0;
  width: 100%;
  box-sizing: border-box;
  background-color: white;
  display: flex;
  justify-content: space-between;
  align-items: center;
  height: 46px;
  line-height: 46px;
  padding-left: 10px;
  .ipt-cmt-div {
    flex: 1;
    border: 1px solid #efefef;
    border-radius: 15px;
    height: 30px;
    font-size: 12px;
    line-height: 30px;
    padding-left: 15px;
    margin-left: 10px;
    background-color: #f8f8f8;
  }
  .icon-box {
    width: 40%;
    display: flex;
    justify-content: space-evenly;
    line-height: 0;
  }
}

.child {
  width: 20px;
  height: 20px;
  background: #f2f3f5;
}

// 发布评论的盒子 - 2
.cmt-box {
  position: fixed;
  bottom: 0;
  left: 0;
  width: 100%;
  height: 80px;
  display: flex;
  justify-content: space-between;
  align-items: center;
  font-size: 12px;
  padding-left: 10px;
  box-sizing: border-box;
  background-color: white;
  textarea {
    flex: 1;
    height: 66%;
    border: 1px solid #efefef;
    background-color: #f8f8f8;
    resize: none;
    border-radius: 6px;
    padding: 5px;
  }
  .van-button {
    height: 100%;
    border: none;
  }
}
</style>
